Endeavors on the development of efficient and sustainable supported metal catalysts for chemical synthesis on solid–liquid interfaces

Abstract

Supported metal catalysts, particularly for precious metals, have gained increasing attention in green synthetic chemistry. They can make metal-catalyzed organic synthesis more sustainable and economical due to easy separation of product with less metal residue, as well as reusability of the high-cost catalysts. Although great effort has been spent, the precise catalytic mechanism of supported metal-catalyzed reactions has not been clearly elucidated and the development of efficient and stable recyclable catalysts remains challenging. This highlight reveals a “molecular fence” metal stabilization strategy and discloses the metal evolution in Pd-catalyzed C–C bond formation reactions using N-heterocyclic carbene (NHC)-functionalized hypercrosslinked polymer support, wherein the polymeric skeleton isolates or confines the metal species involved in the catalytic reactions, and NHC captures free low-valent metal species in solution and stabilizes them on the support via strong metal-support coordination interaction. This strategy creates a novel route for the development of supported metal catalysts with high stability and provides insights into the reaction mechanism of heterogeneous catalysis.